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Some functions commonly used in PHP dynamic web development_PHP tutorial

WBOY
WBOYOriginal
2016-07-13 17:29:28789browse

在php网页的开头加入以下

以下为引用的内容:
$time_start = getmicrotime();
function getmicrotime()
{
list($usec, $sec) = explode(" ",microtime());
return ((float)$usec + (float)$sec);
}
?>

然后到最后加入以下代码

以下为引用的内容:
$time_end = getmicrotime();
printf ("[页面执行时间: %.2f毫秒] ",($time_end - $time_start)*1000);
?>
 
$file = fopen($filename, r) or die("抱歉,无法打开: $filename");

or在这里是这样理解的,因为在php中并不区分数据类型,所以$file既可以是int也可以bool,所以这样的语句不会报错。但其处理过程可能有些朋友不大明白。

其实在大多数的语言中, bool or bool这样的语句中,如果前一个值为真后一个值就不会再判断了。这里也是的,所以如果fopen函数执行正确的话,会返回一个大于0的int值(这其实就是“真”),后面的语句就不会执行了。如果fopen函数执行失败,就会返回false,那么就会判断后面的表达式是否为真了。

结果执行了die()之后,不管返回什么,程序都已经停止执行了,并且显示指定的出错信息,也就达到了调试的目的。

php复选框的问题

以下为引用的内容:

 
  111
 
  222
 
  333
 
  4444
 
  555
 
  6666
 

d.php

以下为引用的内容:
$fd=$_post[checkbox];
for ($i = 0; $i < (sizeof($fd)); $i++) {
$newhpt=$newhpt.$fd[$i].",";
}
echo $newhpt."
";
?>

php代码中函数前面的@是什么意思?

@的作用是忽略调用该函数时产生的错误信息。

php中日期相加的问题

以下为引用的内容:
$fd=$_post[checkbox];
for ($i = 0; $i < (sizeof($fd)); $i++) {
$newhpt=$newhpt.$fd[$i].",";
}
echo $newhpt."
";
?>

Questions about php watermark

以下为引用的内容:
//读取目标文件
$im = imagecreatefromjpeg("1[2].jpg");
//设定混合模式
imagealphablending($im, true);
//读取水印
$im2 = imagecreatefrompng("watermark.png");
//下面是我写的字,可以不看
//$color = imagecolorallocate($im2, 0, 0, 0);
//imagestring($im2, 12, 1, 1, "i love u jingjing", $color);
//字结束
//拷贝水印到目标文件
imagecopy($im, $im2, 5, 5, 0, 0, 220, 34);
//输出,可以输出到文件里
imagejpeg($im);
imagedestroy($im);
imagedestroy($im1);
?>
$im = imagecreatefromjpeg("1[2].jpg");
//$im = imagecreatefromgif("eee.gif");
//$im = imagecreatefrompng("1[2].png");
$black = imagecolorallocate ($im, 0, 140, 76);
$red = imagecolorallocate ($im, 255, 0, 0);
$string=chr(0xe5).chr(0xae).chr(0x89).chr(0xe5).chr(0xba).chr(0x86).chr(0xe6).chr(0x88).chr(0xbf).chr(0xe4).chr(0xba).chr(0xa7).chr(0xe7).chr(0xbd).chr(0x91);
//imagestring ($im,12,10,10,$string,$red);
imagettftext($im,20,0,4,30,$red,"fzdhtjw.ttf",$string);
imagepng ($im);
imagedestroy ($im);
?>
//这个函数是把汉字转换成utf-8后,就可以在gd中使用了!
function gb2utf8($gb)
{
if(!trim($gb))
return $gb;
$filename="gb2312.txt";
$tmp=file($filename);
$codetable=array();
while(list($key,$value)=each($tmp))
$codetable[hexdec(substr($value,0,6))]=substr($value,7,6);
$utf8="";
while($gb)
{
if (ord(substr($gb,0,1))>127)
{
$this=substr($gb,0,2);
$gb=substr($gb,2,strlen($gb));
$utf8.=u2utf8(hexdec($codetable[hexdec(bin2hex($this))-0x8080]));
}
else
{
$gb=substr($gb,1,strlen($gb));
$utf8.=u2utf8(substr($gb,0,1));
}
}
$ret="";
for($i=0;$i$ret.=chr(substr($utf8,$i,3));
return $ret;
}
function u2utf8($c)
{
for($i=0;$i$str="";
if ($c < 0x80) {
$str.=$c;
}
else if ($c < 0x800) {
$str.=(0xc0 | $c>>6);
$str.=(0x80 | $c & 0x3f);
}
else if ($c < 0x10000) {
$str.=(0xe0 | $c>>12);
$str.=(0x80 | $c>>6 & 0x3f);
$str.=(0x80 | $c & 0x3f);
}
else if ($c < 0x200000) {
$str.=(0xf0 | $c>>18);
$str.=(0x80 | $c>>12 & 0x3f);
$str.=(0x80 | $c>>6 & 0x3f);
$str.=(0x80 | $c & 0x3f);
}
return $str;
}
header("content-type: image/gif");
$im = imagecreate(400,300);
$bkg = imagecolorallocate($im, 0,0,0);
$clr = imagecolorallocate($im, 255,255,255);
$fnt = "wb.ttf";
//include("gb2utf8.php");
$str = gb2utf8("中国");
imagettftext($im, 20, 0, 10, 20, $clr, $fnt, $str);
imagegif($im);
imagedestroy($im);
?>

The following is the quoted content:

//Combined use of javascript and select components
//In the process of writing the program, I want to realize that after selecting the option in the select object,
//No submit button is required , and trigger the action directly, and the selected option must be maintained in the
// page after the action occurs. After describing it, I finally realized this function by using javascript and the onchange attribute and
//value of the select object.
//The code is as follows (the file name is "test.php"):

switch ($mon){

case : echo Please select your zodiac sign:;break;
case 1:echo Your zodiac sign is Aquarius;break;
&

http://www.bkjia.com/PHPjc/531677.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/531677.htmlTechArticleAdd the following quoted content at the beginning of the php page: ? $time_start = getmicrotime(); function getmicrotime( ) { list($usec, $sec) = explode(" ",microtime()); return ((float...
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